1. Field of the Invention
The present invention relates to an automatic welding apparatus for an end plug of a nuclear fuel rod and, more particularly, to an apparatus for automatically welding a cladding tube and an end plug constituting a nuclear fuel rod in an accurate and rapid way using a servo motor.
2. Description of the Related Art
Nuclear reactors are facilities for artificially controlling a fission chain reaction of a fissionable material to use thermal energy generated from nuclear fission as power.
Nuclear fuel used in the nuclear reactor is manufactured by forming concentrated uranium into uniformly sized cylindrical pellets (hereinafter referred to as “sintered compacts”) and then charging a plurality of sintered compacts in a fuel rod. This plurality of fuel rods constitutes a nuclear fuel assembly, wherein the fuel rods are loaded in a reactor core, and are then burnt by a nuclear reaction.
Referring to FIG. 1, the nuclear fuel rod 10 is made up of a cladding tube 11, end plugs 12, sintered compacts 13, and springs. After the sintered compacts 13 and springs are inserted into the cladding tube 11, the end plugs 12 are coupled to open ends, and are welded. After being welded, a weld upset protruding from a weld zone 10a of the cladding tube 11 and the end plug 12 is removed by a machining device.
A plurality of fuel rods manufactured in this way constitutes a nuclear fuel assembly, wherein the fuel rods are loaded in a reactor. Thus, to manufacture the nuclear fuel assembly, many fuel rods are required, and thus welding work of the cladding tube and the end plug is excessively required.
For example, the applicant of the present invention contrived a feeder apparatus for supplying an end plug of a nuclear fuel rod in which the end plug was designed to be automatically supplied to a welding position, and was granted Korean Patent No. 1044336 on Jun. 20, 2011. Further, in Korean Unexamined Patent Application Publication No. 10-2011-0054432 (published on May 25, 2011), a cutting and grinding apparatus for machining a weld zone of an end plug of a nuclear fuel rod by welding a cladding tube and an end plug and then machining a weld upset is disclosed.
Thus, in a process of manufacturing the nuclear fuel assembly requiring many nuclear fuel rods, performing welding work on the cladding tube and the end plug in an accurate and rapid way to improve efficiency and productivity of the work is a very important consideration in manufacturing the nuclear fuel assembly.